Parallel chain drive device

ABSTRACT

A parallel chain drive device for use as a stowable ammunition rammer rod includes two stiff-backed sprocket roller chains that will flex readily when the chains are separated from each other during movement around a pair of chain drive sprockets in one direction and which interlock with each other to resist bending when moved in another direction into parallel paths of travel with respect to each other as driven and guided by the sprockets.

Nelson et 51 Apr. 17, 1973 3 LEL C DRIVE DEVICE Primary ExaminerStephen C. Bentley 75 Inventors: Harry N. Nelson; Donald E. Peck, Attorneyrl Carpemer et both of Indianapolis, Ind.

[57] ABSTRACT [73] Assignee: General Motors Corporation,

Detroit Mich. A parallel chain drive device for use as a stowable ammunition rammer rod includes two stiff-backed Flledi 1971 sprocket roller chains that will flex readily when the [21] APPL No 193,105 chains are separated from each other during movement around a pair of chain drive sprockets in one direction and which interlock with each other to resist U-S- when moved in another direction into parallel [51] Int. Cl. ..F41f 17/16 p ths of travel with respect to each other as driven [58] Field of Search ..89/33 A, 45, 47 and guided by the prockets,

[56] References Cited UNITED STATES PATENTS 4 Claims, 5 Drawing Figures 804,243 1 1/1905 Meigs et a]. ..89/47 PATENTEDAPR 1 71973 SHEET 2 BF 2 w r w [I w .1 7 I I a 5 4? Wi .1 W a l lllW/d j a l 1 l w I J l w ,0, PG (Hf w fi a W air 4' am/wiiiwi 1| 1] a fl w/ I N VEN TORS Hazy ZZ/fe/sozz BY flana/apea A T TORNE Y PARALLEL CHAIN DRIVE DEVICE The invention herein described was made in the course of work under a contract or subcontract thereunder with the Department of Defense.

This invention relates to roller chains and, in particular, to a parallel stiff-backed roller chain device.

In an ammunition loader for a large caliber breech loading gun, such as a tank gun, it is necessary to use a rammer to push a round of ammunition through a loading tube into the breech of the gun. When such a breech loading gun is mounted on a tank, space limitations require that a stowable rammer column or pole be used in lieu of a rigid rammer rod. Such a stowable rammer, in the form of a pair of roller rammer chains, is disclosed, for example, in copending United States application Ser. No. 93,606, now US. Pat. No. 3,670,624 entitled Rammer Head, filed Nov. 30, 1970, in the names of John R. Hayes, Francis H. Eckart and Donald E. Peck assigned to the same assignee as the subject application. The purpose of the rammer chains in such a structure is to form a nearly -foot pole capable of pushing a round of ammunition weighing up to 750 pounds. Double roller chains are the best solution found so far for forming a suitable rod that is capable of folding, as necessary, to meet the space limitations on return from the ramming stroke. In such a ramming device, the maximum load on the roller chains, forming the rammer pole, occurs at the end of the ramming stroke when the round of ammunition is being seated in the breech of the gun. In such a device, since rotation of the chain drive sprocket is used as a feed-back signal of rammer position to the control system of the loading apparatus, any buckling or other shortening of the roller chain rammer rod under load creates a control problem.

It is, therefore, the primary object of this invention to improve a parallel chain drive device for use as a stowable rammer pole in an ammunition loader.

Another object of this invention is to improve a roller chain structure whereby a pair of normally flexible roller chains, when driven in parallel paths to each other, interlock with respect to each other to resist bending and thereby form a substantially rigid rammer pole.

These and other objects of the invention are attained by means of a parallel chain drive device including a pair of sprocket roller chains driven by a pair of sprockets in a first path parallel to each other and in a second path away from each other, one of the chains having alternate sets of support links carrying a lock pin therebetween engageab'le when the chains are moved in the first path by the trailing and leading ends of lock links carried by the other chain and, lock links in one row of links between the alternate sets of support links interlocking the opposite ends between spaced apart portions of an adjacent support link.

For a better understanding of the invention, as well as other objects and further features thereof, reference is had to the following detailed description to be read in connection with the accompanying drawings, wherein:

FIG. 1 is a plan view of the parallel chain drive device of the invention illustrating the chains interlocked with each other when moving in a path parallel to each other and illustrating the flexibility of the chains when they are moved divergent with respect to each other, parts of the chains being broken away to show the details of its construction;

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a view taken along line 3-3 of FIG. 2;

FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG, 2; and,

FIG. 5 is an exploded perspective view with parts broken away of a portion of the sprocket roller chains of FIG. 1.

Referring now to the drawings and, in particular, to FIG. 1, there is illustrated a parallel chain drive device in accordance with the invention which includes a pair of sprocket roller chains 10 and 12 driven and guided by sprockets 14 and 16, respectively. The sprockets I4 and 16, which are driven in synchronization with each other through a suitable drive mechanism, not shown, are positioned relative to each other so that depending on their direction of rotation, they will drive and guide the chains in a first or rammer direction whereby the chains are moved from opposite directions around portions of the sprocket and guided to travel in parallel paths to each other, shown by arrow A in FIG. 1, in interlocking engagement with each other to provide a stiff rammer pole in a manner to be described and, in a second or stowing direction wherein the chains are moved from their parallel paths of travel into diverging paths of travel, as shown by the arrow B in FIG. 1, to permit stowage of the chains. In addition, the sprockets l4 and 16 are mounted vertically with respect to each other so that the chains 10 and 12 are offset relative to each other, as seen in FIG. 2, for a purpose to become apparent.

Referring now to the structure of chain 10, in the embodiment shown, it is a double sprocket roller chain consisting of three rows of links held in spaced apart relation with respect to its adjoining row of links, held in spaced apart relationship from each other by rollers 20 and pivotally secured together by means of roller pins 22, these pins extending through the apertured ends of adjoining links in each row of links and through the rollers in a manner well known in the art. As shown, the top and bottom rows of links, with reference to the figures are composed of conventional links 24, the ends of which are pivotally connected to the next leading and trailing link by roller pins 22.

The center row of links in the structure of chain 10, which may be considered as a double row of links, consists of alternate pairs of links 24 positioned back to back and support links 26 positioned on opposite sides of the ends of links 24. Support links 26 are provided with an intermediate support portion 26a extending at right angles from the path of movement of the roller pins 22 in the direction of arrow A, toward roller chain 12 as seen in FIG. 1. The support links 26 carry between them a trapezoidal lock member 28 which may be secured between the support portions 26a in a suitable manner such as by rivets or welding, as shown. As shown in FIG. 1, the leading edge of each lock member 28, in terms of the direction of travel as shown by arrow A, is notched at 28a to partly encircle lock pins 34 carried by chain 12 and its trailing edge is also notched at 28b in a reverse configuration from that of notch 28a to also engage a lock pin.

Sprocket roller chain 12, in the embodiment shown, is also a double roller chain consisting of three rows of links spaced apart from each other by rollers 20 and pivotally secured together by means of roller pins 22 in the same manner as previously described, reference to sprocket roller chain 10.

However, roller chain 12 is offset with respect to roller chain so that, in the embodiment disclosed, the center row of links of chain 10 will be positionable between the top and center row of links of chain 12 for a purpose to become apparent. This means, of course, with respect to the drawings, that the sprocket 16 for roller chain 12 is vertically lower than sprocket 14 for roller chain 10.

As shown, the top row of links of the sprocket roller chain 10 with reference to the figures is composed of alternating conventional links 24 and support links 30, the latter being provided with support portions 30a so that this link is similar in appearance to the support links 26 of sprocket roller chain 10. The center row of links, which is actually a double row of links, consists of alternate support links 26 together with the support portions 26a thereon between which are secured lock member 38 and stepped support links 32 with support portions 320 projecting therefrom. The stepped support links 32 are positioned face to face with respect to each other so that the support portions 320 thereof are in spaced apart relation to each other, this spacing being sufficient so as to slidably receive the lock members 38 therein of the next adjacent link 26. Each adjoining set of support links 30 and 32 support a shouldered lock pin 34, the lock pin extending through a suitable aperture 30b in support link 30 and apertures 32b in each support portion 32a of support links 32 with the shoulder 34a of the lock pin abutting against the inboard face of support link 30.

The opposing sets of support links 26 in chain 12, like their counterparts in chain 10, are provided with support portions 26a to support between them a trapezoidal lock member 38 with opposite ends thereof tapered as at 38a, as seen in FIG. 4, for ease of entry of these ends of lock member between the spaced apart support portions 32a of support links 32. The interlocking relationship between the locking members 38 and the spaced apart portions 32a of support links 32 made the chain 12 relatively rigid against vertical displacement of this chain, with reference to FIG. 2. This rigidity of chain 12 also effects favorably on the rigidity of chain 10 when these chains are interlocked together to form the rammer pole, that is, when the chains are moving in the direction of arrow A in FIG. 1. The third or bottom row of links of sprocket roller chain 12 consists, in the embodiment disclosed, of conventional links 24 connected together in a manner previously described.

The leading ends of sprocket roller chains 10 and 12, with respect to their travel in the direction of arrow A in FIG. I, that is, the leftmost ends of these chains as seen in this figure, are connected together to a rammer head, not shown, since it forms no part of the subject invention, which may be of the type disclosed in the above-referenced United States application Ser. No. 93,606.

In operation, bottom sprocket roller chains 10 and 12 are stowable when moved out of parallel interconnecting paths of movement with respect to each other, as when moved in diverging directions with respect to each other in the direction of the arrow B as seen in FIG. 1, with all of the links of a chain being pivotable with with respect to their leading and trailing links. However, when sprocket 14 is rotated clockwise and sprocket 16 is rotated counterclockwise, the sprocket roller chains 10 and 12 are moved from opposite directions around their respective sprockets to merge together in interlocking relationship with respect to each other to then travel in parallel paths with each other to form a stiff rammer pole moving in the direction of arrow A AS seen in FIG. 1.

As the respective links of the roller chains 10 and 12 move toward each other around the sprockets l4 and 16, the trailing edge portion 28b ofa lock member 28 is first moved into a straight line path of travel and as this occurs, a lock pin 34 on the chain 12 will move into abutting relationship behind this notched portion 28b, in terms of the direction of travel of the chain, after which the next succeeding lock member 28 will be moved in an arc whereby its notched portion 28a will be guided to partly encircle the lock pin 34 and, once this occurs, as seen in FIG. 1, the lock portions 28a and 28b and pin 34 thus interlocked or latched together will prevent transverse separation of the chain with respect to each other. In addition, since the trailing edge of one lock member and the leading edge of the next lock member butt against opposite sides of the lock pin, longitudinal deflection or buckling of the chains 10 and 12 will be prevented and thereby assuring a stiff rammer pole. Thus, with this double rammer chain construction, rotation of either of the chain drive sprockets l4 and 16 can be used as an accurate feedback signal of rammer position to the control system of the loading apparatus for the gun.

As can be seen in FIG. 1, when the direction of rotation of the sprockets 14 and 16 is then reversed from that described above, the various portions of the roller chains 10 and 12 will become disengaged from each other in the reverse manner as described above whereby these chains will become independently flexible to permit stowage of each chain.

What is claimed is:

1. A parallel chain drive device including a first roller chain means, a second roller chain means, said first roller chain means and said second roller chain means, each including at least a first row of link means and a second row of link means with rollers and pin means connecting the adjacent link means of each respective row of link means together with said rollers positioned between the first row and second row of link means to maintain them in spaced apart relationship to each other, a first drive sprocket in driving engagement with said first roller chain means, a second drive sprocket in driving engagement with said second roller chain means and positioned relative to said first drive sprocket whereby said drive sprockets effect movement of said first roller chain means and said second roller chain means in a first direction in parallel paths in closely spaced relation to each other and in a second direction wherein said first and second roller chain means are separated from each other and to position said first roller chain means so that its second row of links is positioned intermediate said first row and said second row of link means of said second roller chain means, said first and second rows of link means of said second roller chain means containing alternate support member links supporting a lock pin therebetween and,

said second row of link means of said first roller chain means including alternate support links, and locking members fixed to each of said supporting members, said locking members having opposite ends thereof notched so as to partly encircle the locking pins with which it cooperates when said first and said second roller chain means are moved in aid first direction.

2. A parallel chain drive device according to claim 1 wherein said support member links of said second row of link means of said second roller chain means consists of a stepped support means with support portions thereon positioned in spaced apart relation to each other, said second row of link means further including support links with a locking member thereon, each of said support links being pivotally connected at opposite ends to a leading and trailing support member links, in terms of the direction of roller chain means travel, each of said locking members of said support links being slidable at opposite ends thereof between said support portions of said leading and trailing support member links when moved in aid first direction.

3. A parallel chain drive device including a first roller chain means, a second roller chain means, a first drive sprocket in driving engagement with said first roller chain means, a second drive sprocket in driving engagement with said second roller chain means, said drive sprockets being positioned relative to each other whereby to effect movement of said roller chain means in a first direction wherein said roller chain means are moved in parallel paths and in closely spaced relation to each other and in a second direction wherein said roller chain'means are flexed and separated from each other, said first roller chain means and said second roller chain means each including at least two rows of link means, roller and pin means connecting the adjacent link means of each respective row together with said rollers positioned between the rows of link means to maintain them in spaced apart relationship to each other, said second roller chain means being positioned relative to said first roller chain means when driven in said first direction so that the rows of said link means of said second roller chain means straddle a row of said link means of said first roller chain drive means, the rows of link means of said second roller chain means including alternate support links having a pin support portion extending toward said first roller chain means in terms of their relative position when moved in said first direction, a lock pin secured between adjacent pairs of said support links, the row of said link means of said first roller chain means straddled by said link means of said second roller chain means including alternate lock links having leading and trailing edge portions, in terms of the direction of travel in said first direction, adapted to engage around said lock pin when said roller chain means are traveling in said first direction in parallel relationship to each other.

4. A parallel chain drive device according to claim 3 wherein one row of said second roller chain means including said alternate support links includes lock links pivotally secured to opposite ends of said support links with each of said support links consisting of a stepped support means with support portions thereon positioned in spaced apart relation to each other to slidably receive the ends of the next adjacent lock links. 

1. A parallel chain drive device including a first roller chain means, a second roller chain means, said first roller chain means and said second roller chain means, each including at least a first row of link means and a second row of link means with rollers and pin means connecting the adjacent link means of each respective row of link means together with said rollers positioned between the first row and second row of link means to maintain them in spaced apart relationship to each other, a first drive sprocket in driving engagement with said first roller chain means, a second drive sprocket in driving engagement with said second roller chain means and positioned relative to said first drive sprocket whereby said drive sprockets effect movement of said first roller chain means and said second roller chain means in a first direction in parallel paths in closely spaced relation to each other and in a second direction wherein said first and second roller chain means are separated from each other and to position said first roller chain means so that its second row of links is positioned intermediate said first row and said second row of link means of said second roller chain means, said first and second rows of link means of said second roller chain means containing alternate support member links supporting a lock pin therebetween and, said second row of link means of said first roller chain means including alternate support links, and locking members fixed to each of said supporting members, said locking members having opposite ends thereof notched so as to partly encircle the locking pins with which it cooperates when said first and said second roller chain means are moved in said first direction.
 2. A parallel chain drive device according to claim 1 wherein said support member links of said second row of link means of said second roller chain means consists of a stepped support means with support portions thereon positioned in spaced apart relation to each other, said second row of link means further including support links with a locking member thereon, each of said support links being pivotally connected at opposite ends to a leading and trailing support member links, in terms of the direction of roller chain means travel, each of said locking members of said support links being slidable at opposite ends thereof between said support portions of said leading and trailing support member links when moved in said first direction.
 3. A parallel chain drive device including a first roller chain means, a second roller chain means, a first drive sprocket in driving engagement with said first roller chain means, a second drive sprocket in driving engagement witH said second roller chain means, said drive sprockets being positioned relative to each other whereby to effect movement of said roller chain means in a first direction wherein said roller chain means are moved in parallel paths and in closely spaced relation to each other and in a second direction wherein said roller chain means are flexed and separated from each other, said first roller chain means and said second roller chain means each including at least two rows of link means, roller and pin means connecting the adjacent link means of each respective row together with said rollers positioned between the rows of link means to maintain them in spaced apart relationship to each other, said second roller chain means being positioned relative to said first roller chain means when driven in said first direction so that the rows of said link means of said second roller chain means straddle a row of said link means of said first roller chain drive means, the rows of link means of said second roller chain means including alternate support links having a pin support portion extending toward said first roller chain means in terms of their relative position when moved in said first direction, a lock pin secured between adjacent pairs of said support links, the row of said link means of said first roller chain means straddled by said link means of said second roller chain means including alternate lock links having leading and trailing edge portions, in terms of the direction of travel in said first direction, adapted to engage around said lock pin when said roller chain means are traveling in said first direction in parallel relationship to each other.
 4. A parallel chain drive device according to claim 3 wherein one row of said second roller chain means including said alternate support links includes lock links pivotally secured to opposite ends of said support links with each of said support links consisting of a stepped support means with support portions thereon positioned in spaced apart relation to each other to slidably receive the ends of the next adjacent lock links. 